As represented by Japanese Patent Application No. S41-00563 described below, a spheronizer for transforming wet columnar particles into spherical shapes is known. In the spheronizer, the columnar particles, which remain in a wet condition, as a raw material are fed into a cylindrical hollow case. On a bottom within the hollow case, a disc having engraved irregularities is rotated. Concurrently therewith, the fed wet columnar particles are smashed and transformed into spherical shapes.
As a result of the use of the spheronizer, there is a concern that the irregularities on the rotating disc are clogged with wet powders generated from the raw material. In particular, as described in Japanese Patent No. 3886165 described below, irregularities along an outer circumference of the rotating disc are easily clogged. The rotating disc of which the irregularities are clogged is inferior in the effect of regulating particles into spherical shapes, and thus, cleaning the clogged rotating disc becomes necessary.
Conventionally, the cleaning is performed in a state that an operation of the spheronizer is stopped by scraping the wet powders clogged in the irregularities of the rotating disc using a spatula or a brush. However, this operation requires a significant amount of labor and time. The scraping with the spatula or the brush may generate metal fragments which could be mixed in a product. On the other hand, when cleaning by using water is additionally applied, it is effective, but requires drying or wiping, and thereby takes a long time to complete the operation. In addition, should the water or drug solution remain, a defective product may be produced.
In view of these circumstances, in Japanese Patent No. 3886165 described below, not forming the irregularities along the outer circumference of the rotating disc has been proposed. This is intended to solve the problem by not forming the irregularities at positions most likely to be clogged.